Remove GetPendingSiteInstance from NavigationControllerDelegate.

content/browser/frame_host/navigation_controller_impl.cc

Index: content/browser/frame_host/navigation_controller_impl.cc
diff --git a/content/browser/frame_host/navigation_controller_impl.cc b/content/browser/frame_host/navigation_controller_impl.cc
index 01da9c130f57d116b8f931aa1b342e906fe7d8d5..c49426b01c2fd88b73a23501e47418d9e362f3a3 100644
--- a/content/browser/frame_host/navigation_controller_impl.cc
+++ b/content/browser/frame_host/navigation_controller_impl.cc
@@ -813,10 +813,15 @@ bool NavigationControllerImpl::RendererDidNavigate(
     details->previous_entry_index = -1;
   }
 
-  // If we have a pending entry at this point, it should have a SiteInstance.
-  // Restored entries start out with a null SiteInstance, but we should have
-  // assigned one in NavigateToPendingEntry.
-  DCHECK(pending_entry_index_ == -1 || pending_entry_->site_instance());
+  // If there is a pending entry at this point, it should have a SiteInstance,
+  // except for restored entries.
+  DCHECK(pending_entry_index_ == -1 ||
+         pending_entry_->site_instance() != nullptr ||
+         pending_entry_->restore_type() != NavigationEntryImpl::RESTORE_NONE);
+  if (pending_entry_index_ != -1 &&
+      pending_entry_->site_instance() == nullptr &&
+      pending_entry_->restore_type() != NavigationEntryImpl::RESTORE_NONE)

[Charlie Reis, 2015/07/30 16:55:14]

Let's simplify these to:

DCHECK(!pending_entry_ || pending_entry_->site_instance() || ...restore...);
if (pending_entry_ && pending_entry_->restore_type() != ...)
  ...set_restore_type...


Reasoning:
1) pending_entry_index_ isn't quite sufficient, even in the old check. 
pending_entry_ can be set even when the index is -1, which corresponds to a new
navigation.  Those won't be session restore cases, but they should have a
SiteInstance.
2) No need for the "== nullptr", since most of the code around here doesn't use
that (e.g., line 808, 871, etc).
3) The SiteInstance check in the if block isn't really necessary (though I agree
we had it before).  If it's a restore, we should clear the restore type, whether
it has a SiteInstance already or not.

[Fabrice (no longer in Chrome), 2015/07/30 17:18:41]

Done.
I find the explicit nullptr comparison to be easier to read and it seems some of
the more recent code and tests have adopted this - though I agree it's
semantically identical.

+    pending_entry_->set_restore_type(NavigationEntryImpl::RESTORE_NONE);
 
   // If we are doing a cross-site reload, we need to replace the existing
   // navigation entry, not add another entry to the history. This has the side
@@ -1157,7 +1162,7 @@ void NavigationControllerImpl::RendererDidNavigateToExistingPage(
 
   // The site instance will normally be the same except during session restore,
   // when no site instance will be assigned.
-  DCHECK(entry->site_instance() == NULL ||
+  DCHECK(entry->site_instance() == nullptr ||
          entry->site_instance() == rfh->GetSiteInstance());
   entry->set_site_instance(
       static_cast<SiteInstanceImpl*>(rfh->GetSiteInstance()));
@@ -1723,15 +1728,6 @@ void NavigationControllerImpl::NavigateToPendingEntry(ReloadType reload_type) {
 
   if (!success)
     DiscardNonCommittedEntries();
-
-  // If the entry is being restored and doesn't have a SiteInstance yet, fill
-  // it in now that we know. This allows us to find the entry when it commits.
-  if (pending_entry_ && !pending_entry_->site_instance() &&
-      pending_entry_->restore_type() != NavigationEntryImpl::RESTORE_NONE) {
-    pending_entry_->set_site_instance(static_cast<SiteInstanceImpl*>(
-        delegate_->GetPendingSiteInstance()));
-    pending_entry_->set_restore_type(NavigationEntryImpl::RESTORE_NONE);
-  }
 }
 
 bool NavigationControllerImpl::NavigateToPendingEntryInternal(